The present invention relates to a blade for the photooptical shutters of optical instruments, for example, photographic cameras or photographic objectives.
Blades of this type had been made heretofore mainly of steel, in particular from spring steel strip by stamping. The blades obtained as individual parts must be deburred and, in order to prevent surface reflections, provided with a black, matte or no-gloss coating and prior to that suitably prepared for this working process. Furthermore, the blades require adequate mechanical stability in view of the intermittently occurring high forces during acceleration and braking, particularly in the areas of the recesses for support and control purposes. The said recesses are therefore provided with rivetted reinforcements, which again require a considerable expenditure of time in the case of the blades which are present individually.
In view of the relatively high production costs, shutter blades made of a thermoplastic synthetic plastic material have become known. These may be produced in a single working step in an injection molding tool. In the process, several shutter blades may be produced in a single working step simultaneously and provided with a matte surface by means of the surface treatment of the cavities of the tool by sand blasting, etching or the like. The supporting journals, pins or the like provided for the support and control of the shutter blades are injection molded right into the part. However, the durability and hardness of such plastic blades is less than those of steel blades.